Railway traffic controlling apparatus



Nov. 24, 1936. B. E. OHAGAN RAILWAY TRAFFIC CONTROLLING APPARATUS FiledJuly 5, 1955 Sw @N LIN m @CSW Amm.

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Patented Nov. 24, 1936 UNITED STTES PATENT OFFIQE RAILWAY TRAFFIC CONTROLLING APPARATUS Application .lilly 3, 1935, Serial No. 29,657

9 Claims.

My invention relates to railway traffic controlling apparatus, and more specifically to apparatus for the elimination of interference caused by propulsion current harmonics or other foreign cur- ,rent with the operation of the wayside signal equipment.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic *.view showing an alternating current track circuit and the associated wayside signaling apparatus embodying my invention.

Referring to the drawing, the trafc rails l and la of a track section D E are supplied with alternating current of a given frequency such as, for example, 60 cycles per second, from the secondary winding 2 of a transformer Tl, which is 4connected across the rails at one end of the ysection for the purpose of energizing a track relay R connected across the rails at the other end of the section, and for the additional purpose of supplying coded track circuit current for the operation of locomotive carried train control equipment. The track relay R is of the two element type which requires simultaneous energization of both the windings 3 and 4 with currents of proper relative polarities for operation. As here shown, the track winding 3 of relay R is energized from the secondary Winding 2 of transformer Tl over the track rails of the section D E as explained above, and the local winding 4 is (energized from a secondary winding 38 of the transformer TI over a line circuit to be described later. If the rails of section D E carry alternating propulsion current having a harmonic frerelay R. In order to eliminate the possibility of false pick up of relay R and to decrease such interference in its operation, the relative polarities of the currents supplied to the windings 3 and 4 of relay R are periodically and simultaneously reversed, whereby this relay becomes incapable of retaining its energized position by the energization of either winding with steady alternating current even if that current be of the (ci. 24e-34)' proper frequency and phase relation. Furthermore, in the event of a blown fuse or other fault in the primary winding side of the line transformer supplying the apparatus with signaling current, current of the propulsion frequency supplied back through the track transformer Tl to the signal system due to an unbalanced track condition may energize the signaling apparatus exactly as though the power was being received from the signal tr-ansmission line. In order to eliminate the possibility of such feed back of propulsion current, I provide a check relay CR of the two element type, one element of which is energized from the secondary winding of the yline transformer and the other element of which is energized from the transmission line by a separate or independent transformer, as will be described hereinafter.

As a means for periodically reversing the relative polarities of the currents supplied to the windings 3 and 4 of the relay R, a flasher or oscillating rel-ay FR is provided which when energized causes contacts 5 6 and 5 1 to be alternately and periodically closed thereby alternately supplying current, as will shortly be described, from the secondary winding 8 of a line transformer T2 to the two portions 9 and l0 of the primary winding of the transformer Tl, the secondary windings 2 and 38 of which supply current to the windings 3 and 4 as stated above. The primary winding Il of the line transformer T2 is in turn connected with the transmission line l2 |3 which receives alternating signaling current from any convenient source such as a generator not shown.

When the section D E is unoccupied, an approach relay V is energized over front contact 44 of relay R and alternating current in a steady energy condition is fed to the pole-changing contacts of the relay FR and thence to the primary winding of transformer Il over two circuits which are alternately and periodically closed. During the interval the contact 5 6 of relay FR is closed as illustrated in the drawing, a circuit can be traced from the BX terminal of winding 8 of transformer T2 over wire 25, front contact 26 of relay V, wire I4, contact 5 6 of relay FR, wire I5, arm I6 of a full wave rectier Rl, wire I1, winding of a relay I8 to be referred toflater, wire I9, arm 20 of rectier Rl, wire 2|, left-hand portion 9 of primary winding of transformer Tl to the midterminal, wire 22, front cont-act 23 of check relay CR, and wire 24 to the CX terminal of the winding 8. During the half cycle of the alternating current the terminal CX of winding 8 is of positive polarity, the current flowing in the above traced circuit passes through the two arms 21 and 28 of the rectifier RI in place of the arms I6 and 20 as is the case during the half cycle the BX terminal is of positive polarity, with the result that current flows in the winding of direct current relay I8 always in the same direction and that relay is energized in series with the portion 9 of the primary winding of transformer TI. During the interval the contact 5--1 of relay FR is closed, -a circuit is completed from the BX terminal of secondary winding 8 over wire 25, front contact 26 of relay V, wire I4, contact 5-1 of relay FR, wire 29, arm 30 of a rectifier R2, wire 3I, winding of a relay 32 to be referred to later, wire 33, arm 34 of rectifier R2, wire 35, right-hand portion I of the primary winding of transformer TI to the midterminal, wire 22, front contact 23 of relay CR and thence over wire 24 to the CX terminal of winding 8. During the half cycle of the alternating current the terminal CX is of positive polarity, the current flowing in this latter circuit passes through the arms 36 and 3'! of rectifier R2 with the result that the current always flows in the winding of direct current relay 32 in the same direction and that relay is energized in series with the portion I0 of the primary winding of transformer TI. The direct current relays I8 and 32 are each provided with slow release periods and remain energized from one impulse to the next.

The electromotive forces induced in the secondary winding 2 of transformer TI in response to impulses of current supplied to the two portions 9'and I8 of the primary winding are effective in each case to energize the winding 3 of relay R over the traffic rails as explained hereinbefore. The electromotive forces induced in the secondary winding 38 in response to impulses of alternating current supplied to the two portions 9 and I9 of the primary winding of transformer TI are effective to energize the winding 4 of relay R over a line circuit which may be traced from the right-hand terminal of winding 38 over line wire 39, winding 4 of relay R, line wire 49, front cont-act 4I of relay I8, front contact 42 of relay 32, and wire 43 to the left-hand terminal of winding 38. It follows that during the interval contact 5-B of relay FR is closed, the secondary Windings 2 and 38 of transformer TI supply currents of one relative polarity to the windings 3 and 4, and during the interval the contact 5-1 is closed the relative polarity of the currents supplied to the windings 3 and 4 is reversed. It is clear, however, that proper phase relation for effectively energizing the relay under each condition is maintained. The track relay R and the oscillating relay FR, are so proportioned and adjusted that the open circuit period while the oscillating member 5 is moving between the contacts 6 and 1 is sufficiently short to prevent release of the relay, and the closed circuit interval during which the oscillating member 5 is in engagement with either contact 6 or Contact I is sufiiciently short that the relay will not close its front contacts on but one such interval.

When the section D-E is occupied, front contact 44 of relay R opens deenergizing approach relay V, and -a code transmitter CT is then energized over a back contact 45 of relay V. The code transmitter CT is so designed the contact fingers |80, |20, and 80 operate at a speed of 180, 120, and 80 movements per minute, respectively, to code the alternating current fed acci/ir from the secondary winding 8 to the pole-chang'- ing contacts of relay FR. The code speed effective at any particular time is dependent upon traffic conditions in advance of section D-E, as determined by the signal selection apparatus which forms no part of my invention yand which is not shown in the drawing for the sake of simplicity. The track relay R is designed in such manner that it will pick up on the coded current supplied to the windings 3 and 4 when the relative polarities of the coded currents are periodically and simultaneously reversed with the result that as soon as a train vacates the section D E, the relay R will pick up energizing approach relay V over front contact 44 and deenergizing the code transmitter CT at the b-ack contact 45. It will be understood, of course, that to provide for operation of the locomotive carried train control equipment, the code transmitter CT and the oscillating relay FR are so designed there is a proper time interval between reversals of current supplied to the track circuit for producing the proper off intervals of the code.

It will be apparent that if the normal supply of current to the winding 3 of relay R is interrupted for any reason, such as a rail broken or a train occupying the section DE, it will not be possible for a foreign current such as a harmonic current of propulsion power, which is of a constant relative polarity to pick up relay R because of the periodic reversal of the relative polarity of the signaling current supplied to the local Winding 4. Furthermore, with apparatus arranged in accordance with my invention, it is impossible for local Winding 4 of the relay R to receive a harmonic of the propulsion current fed back through the transformer TI in opposition to the normal supply of signaling current.

Apparatus as thus far described would be safe in discriminating against a harmonic frequency which is app-roximately the same as the signaling frequency, except in the case where the primary winding of the line transformer T2 should be open-circuited either due to a blown fuse or other fault, and current of the harmonic frequency fed into the signal circuits from the propulsion system would operate the oscillating relay and all other associated apparatus exactly as though the power was being received from the signal transmission line. In order to avoid this possibility, I provide, as explained hereinbefore, a two element check relay CR to control the common side of the power supplied to the equipment. The element 49 of relay CR is energized from the secondary side of the line transformer T2 while the other element 41 of relay CR is energized either from a small separate line transformer T3 or over a pair of line Wires 48 and 49 from an adjacent signal location. When the equipment is thus arranged and a fuse such as 59 or 5I of the line transformer T2 is blown, the element 46 of relay CR might be energized by current fed from the track back through the transformer TI and the pole-changing contacts, but the other element 41 of relay CR would be energized by signaling current which is not pole-changed and the result would be that relay CR would not keep its front contacts closed and all of the signaling apparatus would become deenergized. The two slow releasing direct current relays I8 and 32 are effective to insure that the signaling power supplied to the winding 4 of relay R is being pole-changed. In the event the contact member 5 of relay FR should stick on one side or b-ecome inoperative with both contacts open, one or both relays I8 and 32 would be deenergized and the line circuit for the winding 4 would be opened.

Although I have herein shown the apparatus embodying my invention applied to the wayside signal equipment suitable for use in connection with a code system of train control, the apparatus is equally well adapted tothe control of wayside equipment without train control or with any other suitable system of train control.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that vario-us changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a section of railway track, a relay having two cooperating windings one of which receives current from the rails of said section, a transformer provided with two secondary windings and a primary winding having a midterminal, means to supply current from one secondary winding to the rails of the section, other means to supply current from the other second- 'ary winding to the other one of said relay windings, a source of alternating signaling current, means to connect one terminal of the source with said midterminal, and means including an oscillating contact to alternately connect the other terminal of the source to the opposite outside terminals of said primary winding to cause the current to flow first in one portion of the primary winding and then in the other portion of the winding whereby the relative polarities of the currents supplied to the two relay windings are periodically and simultaneously reversed.

2. In combination, a section of railway track, a relay having two cooperating windings one of which receives current from the rails of said section, a transformer provided with two secondary windings and a primary winding having a midterminal, means to supply current from one secondary winding to the rails of the section, other means to supply current from the other secondary winding to the other one of the relay windings, a line transformer, means to connect one terminal of the secondary winding of said line' transformer with the midterminal of the primary winding of the first mentioned transformer, means including an oscillating contact to alternately connect the other terminal of the secondary winding of the line transformer with the outside terminals of the primary winding of the first mentioned transformer, and means to supply the primary winding of the line transformer with an alternating signaling current.

3. In combination, a section of railway track, a track relay having two cooperating windings one of which receives current from the rails of said section, a transformer provided with two secondary windings and a primary winding having a midterminal, means to supply current from one secondary winding tothe rails of the section, other means to supply current from the other secondary winding to the other one of the track relay windings, a line transformer, a check relay having two cooperating windings one of which receives current from the secondary winding of the line transformer, means including a front contact of the check relay to connect one terminal of the secondary winding of the line transformer to said midterminal of the primary winding of the first mentioned transformer, means including an oscillating contact to alternately connect the' other terminal of the secondary winding of the line transformer with the outside terminals of the primary winding of the rst mentioned transformer, and means to supply an alternating signaling current to the primary winding of the line transformer and to the other winding of the check relay.

4. In combination, a section of railway track, a track relay having two cooperating windings one of which receives current from the rails of said section, ja transformer provided with' two secondary windings and a primary winding having a midterminal, means to supply current from one secondary winding to the rails of the sectio-n, other means to supply current from the other secondary winding to the other one of the track relay windings, a line transformer, means to connect one terminal of the secondary winding of the line transformer to said midterminal of the primary winding of the first mentioned transformer, means including an oscillating contact to alternately connect the other terminal of the secondary winding of the line transformer with the outside terminals of the primary winding of the first mentioned transformer, means including a source of alternating signaling current connected to the primary winding of the line transformer, and means including a relay having two cooperating windings one of which receives current from the secondary winding of the line transformer and the other of which receives current direct from the source for checking the supply of current from the line transformer to the first mentioned transformer.

5. In combination, a section of railway track, a track relay having two cooperating windings one of which receives current from the rails of said section, a transformer provided with two secondary windings and a primary winding having a midterminal, means to supply current from one secondary winding to the rails of the section, other means to supply current from the other secondary winding to the other one of the track relay windings, a source of alternating signaling current, a check relay, means including a front contact of the check relay to connect one terminal of said source tosaid midterminal of the primary winding of the transformer, means including an oscillating contact to alternately connect the other terminal of said source with the outside terminals of the primary winding of the transformer, and means for energizing said check relay from said source.

6. In combination, a section of railway track, a track relay having two cooperating windings one of which receives current from the rails of said section, a transformer provided with two secondary windings and a primary winding having a midterminal, means to supply current from one secondary winding to the rails of the section, a rst and a second relay, means including a front contact of each of the first and second relays to supply current from the other secondary winding to the other one of the track relay windings, a source of alternating signaling current, means to connect one terminal of said source with the midterminal of said primary winding, an oscillating relay; a first circuit means to connect the other terminal of said source with one of the outside terminals of said primary winding and including a front contact of said oscillating relay, a rst rectifier and the winding of said first relay; and a second circuit means to connect said other terminal of the source with the other outside terminal of said primary winding and including a back contact of said oscillating relay, a second rectier and the winding of said second relay.

7. In combination, a section of railway track, a relay having two cooperating windings one of which receives current from the rails of said section, a transformer provided with two secondary windings and a primary winding having a midterminal, means to supply current from one secondary winding to the rails of the section, other means to supply current from the other secondary winding to the other one of said relay windings, a source of alternating signaling current, a code transmitter having code contacts each adaptable of being operated at a particular speed corresponding to a given signal selection, an oscillating relay having a contact member adaptable of alternately engaging a pair of contacts, means to connect said pair of contacts to the outside terminals of said primary winding respectively, means to connect one terminal of said source with said midterminal, traffic controlled means to connect the other terminal of said source with said contact member and including said code contacts, and other traffic controlled means to connect said other lterminal of the source directly with said contact member.

8. In combination, a section of railway track, a relay having two cooperating windings one of which receives current from the rails of said section, a transformer provided with two secondary windings and a primary winding having a midterminal, means to supply current from one secondary winding to the rails of the section, other means to supply current from the other secondary winding to the other one of said relay windings, a source of alternating signaling current, means including an oscillating contact to alternately and periodically connect the source between the midterminal and the opposite outside terminal of said primary whereby the relative polarities of the currents supplied to the two relay windings are periodically and simultaneously reversed, a code transmitter having different code contacts adaptable of being operated at different speeds corresponding to different signal selections, and traffic controlled means to at times interpose said code contacts between the source and said oscillating Contact,

9. In combination, a transformer provided with a primary winding having a midterminal, a source of alternating current, a first and a second relay, an oscillating relay having a contact member adapted to alternately engage a pair of contacts, means to connect one terminal of said source with said midterminal; a rst circuit means to connect the other terminal of said source with one of the outside terminals of said primary winding and including said contact member, one of said pair of contacts, a first rectiiier and the winding of said rst relay; a second circuit means to connect said other terminal of the source with the other outside terminal of said primary winding and including said Contact member, the other one of said pair of contacts, a second rectier and the winding of said second relay, and a signaling circuit adapted to receive current from a secondary winding of said transformer and including a front contact of each of the iirst and second relays.

BERNARD E. OHAGAN. 

